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arXiv 1503.04070math.AG
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对称函数环的K_T-变形

A K_T-deformation of the ring of symmetric functions

Allen Knutson, Mathias Lederer

摘要:

对称函数的环可以在\union_{a,b} Gr(a,a+b)的同调中实现,乘法结构由“直和“映射定义。存在一个自然的循环作用(同时作用于所有格拉斯曼),在此作用下,每个直和映射都是等变的。用等变K-同调代替通常的同调,得到了对称函数环的一个双参数变形。这个环有一个由舒伯特类给出的模基。几何考虑表明,舒伯特类的乘法在适当的意义下具有正系数。在本文中,我们给出了这些系数的明显的正公式:它们计算具有规定的边缘标记的“DS管道梦”的数量。

英文摘要:

The ring of symmetric functions can be implemented in the homology of \union_{a,b} Gr(a,a+b), the multiplicative structure being defined from the "direct sum" map. There is a natural circle action (simultaneously on all Grassmannians) under which each direct sum map is equivariant. Upon replacing usual homology by equivariant K-homology, we obtain a 2-parameter deformation of the ring of symmetric functions. This ring has a module basis given by Schubert classes. Geometric considerations show that multiplication of Schubert classes has positive coefficients, in an appropriate sense. In this paper we give manifestly positive formulae for these coefficients: they count numbers of "DS pipe dreams'' with prescribed edge labelings.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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